Electric field-induced second-harmonic generation in silicon nanocrystals embedded in a SiO x matrix
Year: 2025
Type: article
Abstract: SiO x films of varying stoichiometry were deposited by plasma-enhanced chemical vapor deposition (PECVD). Applying an annealing process at 1100°C, silicon nanocrystals formed within these films. Subsequently, free-space electric field-induced second-harmonic (EFISH) measurements with a fundamental wavelength of 1030 nm were carried out, demonstrating a voltage-controllable second-order nonlinearity approaching χ (2) values of classic nonlinear crystals, such as KDP ( χ z y x (2) =0.84 p m / V ). Moreover, the EFISH data were evaluated to extract the voltage-independent third-order nonlinearities of the film materials. We observed an increase of more than an order of magnitude of the third-order nonlinearities of the films due to the annealing process. Furthermore, the third-order nonlinearities of as-deposited and annealed films can be strongly enhanced by material composition reaching a maximum of χ (3) = 2.9 × 10 −20 m 2 V −2 for the films with the highest refractive index. To determine the contribution of the nanocrystals to the EFISH effect, we compare the EFISH response of nanocrystal-containing films with that of as-deposited SiO x films without nanocrystals but of the same refractive index. We find that the nanocrystals do not significantly influence the third-order nonlinearities but an increased refractive index does.
Source: Optics Express
DOI: 10.1364/oe.549752
Institution: Paul Drude Institute for Solid State Electronics
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,270
OpenAlex ID: W4407800376